1. Field of the Invention
The present invention relates generally to a glue dispenser, and more particularly to a glue dispensing gun.
2. Description of Related Art
As shown in FIG. 1, a glue dispensing gun of the prior art comprises a barrel 11 to accommodate a glue container 10. The barrel 11 is provided at the rear end with a rear cap 12 which is fastened with a grip 14 having a trigger 13. The top of the grip 14 is fastened with a horizontal center rod 15 whose one end is put through the rear cap 12 to locate in the inside of the barrel 11. The center rod 15 is provided at the front end with an advancing piece 17 which is intended to urge a rear end cover 16 of the glue container 10. The center rod 15 is further provided with a compression spring 18, a pushing piece 19, a recovery spring 20, and a control piece 21. When the center rod 15 is activated by the trigger 13, the pushing piece 19 is actuated to cause the center rod 15 to displace forward so as to push the advancing piece 17, which puts a pressure on the rear end cover 16 of the glue container 10. The barrel 11 is provided at the front end with a front cap 22 and a glue discharging tube 23 for discharging the glue contained in the glue container 10 via the front cap 22.
Such a prior art glue dispensing gun as described above is defective in design because the control piece 21 is urged by the recovery spring 20 to be positioned at an inclination at such time when the center rod 15 displaces forward, thereby preventing the center rod 15 from moving backward. As a result, when the center rod 15 has moved forward to arrive at the final point, the center rod 15 cannot be caused by the trigger 13 to move backward. For this reason, the bottom end of the control piece 21 is pressed by a finger to free the center rod 15, which is then pulled backward with another hand. It is conceivably difficult to use the prior art glue dispensing gun. In addition, the recovery spring 20 and the control piece 21 are not shielded to provide them protection against rust or damage caused by impact.
In short, the prior art glue dispensing gun is inefficient at best.
The primary objective of the present invention is to provide a glue dispensing gun which is efficient and free of the drawbacks of the prior art glue dispensing gun.
The glue dispensing gun of the present invention is basically similar in construction to the prior art glue dispensing gun. The glue dispensing gun of the present invention is characterized by an eccentric transmission member which is disposed in a receiving slot of the rear end of the barrel of the glue dispensing gun and is formed of a guide block, a bearing, and a push block. The guide block is eccentrically pivoted in the receiving slot such that the guide block is fastened with a connection rod of the trigger. The push block is rested against the pushing piece of the center rod. As the trigger is activated, the guide block of the eccentric transmission member is actuated to turn eccentrically so as to cause the push block to push the pushing piece of the center rod, thereby resulting in the forward movement of the center rod. In the meantime, the center rod is retained or released by a retaining piece, depending on the eccentric displacement of the bearing of the eccentric transmission member. The forward motion and the backward motion of the center rod are controlled by the trigger.
The features and the advantages of the present invention will be more readily understood upon a thoughtful deliberation of the following detailed description of a preferred embodiment of the present invention with reference to the accompanying drawings.